Drill bit



J. E WALKER March 16 1926.

DRILL BIT Filed Nov. 4, 1924 INVENTOR JAMES E. WALKER AT TORNE Y.

Patented Mar. 16, 1926.

JAMES E. WALKER, OF LA EAIBRA, CALIFORNIA.

DRILL BIT.

Application filed November 4, 1924. semi- No. W324.

To all whom it may concern:

Be it known that I, JAMES E. WALKER, a citizen of the United States, residing at La Habra, in the county of Orange and State of California, have invented certain new and useful Improvements in.Drill Bits, of which the following is a specification.

It is the object of this invention to rovitle a rotary as large as the outside diameter of'the casing through which the bit is inserted in the bore, so that said casing may be lowered into the bore without necessitating the use of an under-reamer for enlarging the bore to a size adapted to receive the casing.

It is a further object of the invention to provide a drill bit of extremely simple construction, which is adapted to automatically contract while being withdrawn or inserted through the casing of a bore, and automatically expand when .in working position at the bottom of the bore beyond the end of the casing. i

It is a still further object of the invention to provide a drill bit having cutting means comprising a plurality of spikes; and to arrange said spikes so as to cut the bottom of a bore, with the outer spikes also cutting the side walls so as to enlarge the diameter of the bore. I

It is a still further object of the invention to provide a spike drill bit arranged whereby said spikes may be readily removed and replaced when dull; the mounting for said spikes holding the same firmly in place, and automatically expanding and contracting the same, when the bit is in operative position at the bottom of a bore and in inoperative position passing through the easing of the bore, respectively. 7

The invention will be readily understood from the following description of the accompanying drawings, in which:

Fig. 1 is a vertical section through the bore of a well, showing the improved bit expanded to operative position at the bottom of the bore beyond the lower end. of the well casing.

Fig. 2 is a similar view, showing the bit elevated and in contracted position ready to be withdrawn through the well casing.

Fig. 3 is a transverse section on the line 33-of Fig. 1.

Fig. 4 is a bottom plan view of the drill bit with the spike supporting member'removed.

drill bit adapted to cut a ore,

I ventin The improved bit is illustrated as used in connection with a usual rotary drill outfit com rising a casing 1 adapted to be inserted n thebore of awell, with tubing 2 extending therethrough and connected by collar 3 to the nipple 1' of the drill bit.

The drill bit comprises a shell 5 flaring outwardly from nipple 4, and having a member 6 adapted to support the cutting elements, detachably fixed to said shell at its lower end. rangement an upstanding peripheral flange .As an instance of this ar- 7 on the member 6, is adapted for threaded engagement on the lower end of 'shell 5, which is preferably of reduced diameter so that the outer surfaces of the shell and supporting member will lie flush. An axial bore 8 communicating with the bore of tubing 2, extendsthrough nipple 5' and alines with a similar axial bore 9 extending through the supporting member 6, so as to provi e a conduit for discharge of fluid into the bore of the well at the cutting elements of the drill bit.

The cuttin elements of the drill bit consist of a p urality of spikes extending through supporting member 6 with their cutting ends projecting below the same, said spikes having heads adapted to abut against the inner end of member 6 for predisplacement thereof, and adapted to be impinged by the end ofshell 5 for operatively positioning said spikes.

Certain of said spikes shown at 10, extend'through square bores 11 in member 6 adjacent its center; and others of said spikes shown at 12, extend through rectan ular bores 13 in member 6 adjacent its perip ery, the bores 13 being radially elongated as shown in Fig. 1. The spikes 10 and 12 are square ir. crosssection so as to prevent turning thereof in their bores, and the heads 14 of spikes 10 are clamped between shell 5 and supporting member 6 to prevent longitudinal movement of said. spikes, while the heads 15 of spikes 12' are adapted to be received in radial recesses16 formed in the end of shell 5 in alinement with bores 13. Straight cutting edges 17 are preferably formed at the outer sides of the projecting ends of spikes 10 and 12, by inclining said ends of the spikes as shown in Fig. 1.

Spikes 12 are somewhat longer than spikes 10, and the outer ends of recesses 16 form inclined abutment surfaces 18 adapted to beimpinged by curved sides of the heads of spikes 12, so that when the drill bit is lowered in the bore of a well below the end of easing 1 and until the cutting ends of the spikes 12 abut against the bottom of the bore, the spikes 12 will be forced upwardly in recesses 16 and the abutment of heads 15 .against the inclined surfaces 18 will slant the spikes 12 in bores 13 as shown in Fig. 1.

When the cutting 'ends of spikes 12 are in horizontal alinement with those of spikes 10 so that the cutting edges of all the spikes engage the end of the'well bore, the spikes 12 are held against further dlsplacement by the abutment of their heads 15 againstthe upper ends of recesses 16, and with spikes 12 in this position their cutting edges pro ject laterally beyond shell 5 at least as far as the outer periphery of the well caslng as shown in Fig. 1. As a consequence, when the drill is rotated the spikes will cut the central portion of'the well bore, while the spikes 12 enlarge the peripheral portion thereof to a size permitting the casing to be lowered into said bore. The use of an under-reamer subsequent to the boring operation is thus eliminated, the improved bit performing the functions of both a drill and an under-reamer.

When the drill is elevated from the bottom of the well bore, the spikes 12 drop by gravity until their heads 15 abut against supporting member 6 thereby suspendin said spikes parallel td the arms of the bil; as shown in Fig. 2. As a consequence the cutting ends of spikes 12 no longer project beyond the periphery of shell 5, and the bit may thus be readily withdrawn or inserted through casing 1. which is of slightly greater diameter than the shell of the bit.

When the spike drills as thus described are to be replaced, the supporting member 6 may be quickly unscrewed from shell 5, and

.the spikes may then be conveniently withdrawn from their bores and new spikes inserted, after which the member 6 is again fixed to shell 5 by the threaded connection.

It will thus be seen that I have provided an extremely simple construction adapted for automatic expansion and contraction of the cutting elements, and providing simple but practical means for supporting and replacing said cutting mechanism. The use of spike cutting elements also provides a positive cut at a plurality of points so as to form an efficient drill, and the use of separate spikes permits replacement of only such of said elements as are worn or dull.

I claim:

.1. A drill comprising supporting means having a radially elongated longitudinal opening therein forming a shoulder and an inclined abutment surface above the shoulder, and a cutter longitudinally slidable in said opening and havlng a head adapted to either rest upon the shoulder for suspending the cutter parallel to the axis of the drill or impinge against the inclined abutment surface for slanting the cutter in the radially elongated opening so that its projecting cutting edge extends laterally beyond the supporting means.

2. A drill comprising a shell having an end abutment surface and a radial recess therein, said recess forming an inclined abutment surface at the side thereof, a supporting member on the end of the shell having an axial opening and a radially elongated opening extending therethrough, a cutter extending through said axial opening and having a head resting upon the supporting member with the end abutment surface of the shell impinging against said head, and a cutter extending through the radially elongated opening and having a head adapted to either rest upon the supporting member for ,suspending the cutter parallel to the axis of the drill or impinge against the inclined abutment surface for slanting the cutter in the elongated opening so that itsprojecting cutting edge extends laterally beyond the shell.

3. A drill comprising a shell having a radial recess in its end forming an inclined abutment surface at the outer side of said recess, a supporting member on the end of the shell having a radially elongated opening extending longitudinally therethrough, and a cutter longitudinally slidable. in the opening and having a head adapted to either rest upon the supporting member for suspending the cutter parallel to the axis of the drill or impinge against the inclined abutment surface for slanting the cutter in the radially elongated opening so that the projecting end of the cutter extends laterally beyond the shell. A

In testimony whereof I have aifixed my signature to this specification.

JAMES E. WALKER. 

